It is common practice in producing hose assemblies to permanently secure a metal hose coupling onto the end of a hose by plastically deforming or crimping an outer sleeve of the fitting around the hose end to cause the hose to be tightly held between an outer collar or sleeve of the coupling and a fitting nipple positioned inside the hose. In the crimping process, the entire collar of the coupling is engaged by the crimping die of the crimping machine. The crimping die reduces the collar in diameter to secure the coupling to the hose end.
Conventional crimping machines typically have a die plate with a frusto-conical through bore adapted to receive a crimping die with a mating radially outer conical surface. The crimping die is typically constructed from a plurality of pie-shaped segments arranged around a central axial bore. The segments are spaced apart from each other in an expanded mode so as to permit the hose coupling which is to be crimped to be placed in the central bore. The segments are then driven, typically by a hydraulic jack of the crimping machine, into the conical bore of the die plate, which converts the axial movement of the die segments into a radial contraction by the camming action of the conical bore of the die plate. Thus, the die segments are compressed radially so as to make the central bore smaller and causing the radially inner surfaces of the die segments forming the bore to work the metal of the hose coupling and to radially reduce its size.
As the die assembly is typically constructed from a plurality of die segments, usually 4 to 10 in number, it has been found to be useful to provide suitable means for holding a number of such die segments together in either circular or semi-circular arrays to facilitate their handling and use. It has also been found to be useful to provide suitable means for maintaining the segments in a spaced apart relationship prior to the crimping operation and to return the segments to such spaced apart relationship after the crimping operation so as to allow the insertion and removal of the hose coupling from the die assembly. Many prior art die assemblies have attempted to accomplish these functions. For instance in U.S. Pat. No. 4,309,892 issued Jan. 12, 1982 to William E. Currie for a Crimping Machine, each die segment is connected to an adjacent die segment by means of an intermediate rigid link secured by a pair of link pins. In U.S. Pat. No. 3,750,452 issued Aug. 7, 1973 to Irving Frank for a Collet Crimper, the use of individual resilient or rubber spacer members is disclosed. Such spacers are secured to both adjacent die segments by bonding to the adjoining radial surfaces of the segments, thereby both spacing the segments apart and holding the segments together. In U.S. Pat. No. 4,400,967 issued Aug. 30, 1983 to Carl H. Owens for a Crimping Collet, the use of a pair of resilient pads is disclosed for spacing the die segments apart. However in this patent, the pair of pads are only bonded to one of the adjacent segments and thus are used only for spacing purposes. In order to hold the segments of the entire die assembly together, a pair of elastomeric rings are used, which encircle all of the die segments. Such elastic rings are situated in grooves formed in the radially outer surfaces of the die segments.
The various prior attempts at spacing the die segments of a crimping die and in holding the die segments together each have short comings and other problems that limit their usefulness. For instance, some methods make it difficult to remove individual dies segments from the crimping die so that such die segments can be easily replaced when they become worn or damaged. Others methods are subject to bond failure, resulting in the loss of the separating or retention functions altogether and causing damage to the die assembly and/or to the hose coupling. Still others provided exposed grooves or other discontinuities along the radially outer conical surfaces of the die segments, which can produce instability and less mating surface contact between the die segment and the die plate allowing galling or other surface damage to occur. The present invention is directed to overcoming the preceding shortcomings of such prior devices.